What to add to the wall for radiator?

[nameisme]

Hi all,

My radiator came off the wall and a plumber came round and I thought he would fill the holes in the wall but he said it didn't need to be filled in and put holes in another place and put radiator back on wall and assured me it was fine and strong and tested the brackets.

However I would still like to apply something to the holes in the wall he left unfilled.

What can people recommend? Something strong? I can reach it ok from the top with out removing the radiator.

Thanks all

 

[Madrab]

Oh my - is that plaster with brick behind it? Mortar should do the job, pre mixed filler would probably end up cracking with a hole that size. Wet the area first before applying the mortar. Do a first fill leaving a few mm, then once it's dry then add a finishing layer.

 

[nameisme]

Thanks. Im not sure what's behind it.

Is there any mortar that's ready mixed. Ready to use?